Cylindrical radiant energy collectors are trough-shaped nonimaging collectors which concentrate radiant energy. Such collectors are more particularly described in a prior U.S. application for Radiant Energy Collector, Ser. No. 492,074, filed July 25, 1974, and in a publication Solar Energy, Vol. 16, No. 2, pages 89-95, (1974).
It has been observed that such collectors exhibit significant natural convective losses. This arises from the positioning of the energy absorber at the exit aperture. As radiant energy, such as from the sun, is concentrated on the absorber it heats up. Since the heated surface of the absorber is facing upwards towards the entrance aperture, uninhibited convective currents develop, allowing heat to escape the heated surface of the absorber, thereby degrading collector performance.
It is therefore an object of this invention to improve the efficiency of cylindrical radiant energy collectors.
Another object of this invention is to reduce convective heat loss in a cylindrical radiant energy collector.